This invention relates to an electrically actuated brake and more particularly to an improved support for the electromagnet of such a brake.
In one well known type of electrically actuated drum brake, the brake shoes are actuated by pivotal movement of a cammed lever that is supported on the backing plate. The lever carries an electromagnet which, when energized, engages the rotating drum and effects pivotal movement of the lever to actuate the brake shoes. It should be readily apparent that such an arrangement, of necessity, requires certain limited movement of the electromagnet relative to the supporting lever. That is, the electromagnet must move axially relative to the lever to engage the brake drum and must rotate slightly relative to the lever to accommodate the actuating pivotal movement of the lever. Although such relative movements must be afforded, it is also necessary to restrain the degree of movement of the electromagnet relative to the lever to minimize noise, wear and other similar difficulties as well as to transmit the actuating force from the magnet to the lever. A wide variety of constructions have been proposed for accommodating such relative movement while, at the same time, controlling the relative movement. Examples of arrangements which have been proposed for this purpose may be found in the following U.S. Pat. Nos. 3,244,259 issued Apr. 5, 1966 in the name of A. Brede III, et al., and entitled "Electric Brake Mechanism"; 3,476,223 issued Nov. 4, 1969 in the name of H. C. Hubbard, and entitled "Electromagnet"; 3,756,355 issued Sept. 4, 1973 in the name of Carl R. Kreider, and entitled "Electric Brake Construction"; 3,757,264 issued Sept. 4, 1973 in the name of Leroy K. Grove, and entitled "Electromagnet Operating Arm Retaining Means in a Vehicle Brake Structure"; 3,757,903 issued Sept. 11, 1973 in the name of Cletus McLane, and entitled "Electric Brake"; 3,760,909 issued Sept. 25, 1973 in the name of Leroy K. Grove, and entitled "Electromagnet for Brakes and Clutches"; 3,765,517 issued Oct. 16, 1973 in the name of Leroy King Grove, and entitled "Electric Brake Armature"; 4,014,412 issued Mar. 29, 1977 in the name of David L. Swanson, and entitled "Electrically Controlled Brake with Improved Anti-Rotation Bracket for Magnet".
The constructions illustrated in the aforenoted patents generally include an aperture in the electromagnet through which a projection of the lever extends. This construction affords some degree of limited movement. Rotary movement is controlled by having the aperture and projection configured to limit such movement or by including other ancillary structure such as stops for this control. Although the function to be served is relatively simple, the structures previously proposed for achieving the result are relatively complicated, expensive to manufacture and difficult to assemble and service.
It is, therefore, a principal object of the invention to provide an improved electrically actuated brake.
It is another object of the invention to provide an improved, simplified magnet support for such a brake.
It is a further object of the invention to provide an improved and simplified electric brake magnet support that controls the degree of relative movement between the magnet and the supporting lever without adding significantly to manufacturing or assembly costs.